A laser additive manufacturing apparatus and a method thereof are provided. The apparatus includes an irradiation unit that irradiates an irradiation region with a laser beam having a light intensity distribution converted by a diffractive optical element, a head having a material supplying unit for supplying powder material to the irradiation region, and a movement mechanism which relatively moves the head and a workpiece. In the irradiation region, irradiation light forms a substantially circular spot having a light intensity distribution in which light intensity in an outer peripheral portion is higher than light intensity in a central portion, and the central portion has predetermined light intensity, and the material supplying unit supplies the powder material to the substantially circular spot.